1. Field of the Invention
This invention relates generally to the manufacture of stator for dynamoelectric machine field windings. More particularly, the present invention relates to a winding tool for facilitating forming of wire coils in a stator stack for a dynamoelectric machine.
2. Description of the Prior Art
In many conventional dynamoelectric machines, the magnetic stator core comprises a stacked plurality of relatively thin laminations of magnetic material having a central bore which receives the rotor member of the machine. A plurality of slots extend radially inwardly from the bore for receiving the field coils of the machine, wherein such slots are defined by radially extending teeth. A predetermined number of turns of insulated wire conductor are arranged within such slots to form the excitation windings of the motor.
After the coils have been placed within the stator core, the return ends of the coils extend out of the stator slots and beyond the ends of the stator core. For reasons of appearance, as well as customer specifications, the coil ends need to be shaped into a particular desired configuration. Such shaping operations are conventionally referred to as forming or blocking operations. One apparatus for performing such a forming operation is disclosed in U.S. Pat. No. 5,860,615 in which a winding tool is providing with forming racks which may be actuated for extension radially from the sides of the forming tool to intermittently push the end turns of the coils radially outwardly.
It has been observed that during such forming of the end turns of the coils, the wire extending through the slots may tend to flex inwardly toward the center of the stator, and thus reduce the amount of area available for receiving further windings. Accordingly, there has been an observed need for an apparatus to provide the continued advantages associated with providing a tool for forming the end turns of wire coils, while also providing a forming operation for wire located within the slots of the stator.
The present invention resides in a winding tool for forming winding coils in a stator stack for a dynamoelectric machine which satisfies the foregoing needs. The tool comprises, generally, an elongated base structure defining a longitudinal axis, at least one elongated forming blade supported on the base structure and supported for movement, relative to the base structure, in a direction transverse to the longitudinal axis. The at least one forming blade includes an outer edge defining an edge of elongation lying in a plane substantially parallel to the longitudinal axis and an actuator structure is provided, extending through the base structure, for actuating the forming blade in movement whereby the outer edge of the blade is moved from a retracted position to an extended position for insertion through a slot in a stator stack during a winding operation forming wire coils on the stator stack.
In a further aspect of the invention, a plurality of forming blades are provided wherein the actuator structure simultaneously actuates the plurality of forming blades for movement in a radial direction to extend through a plurality of slots in a stator stack. Further, the base structure preferably defines a cylindrical wall, and the outer edges of the forming blades are positioned flush with the cylindrical wall when in the retracted position.
In yet another aspect of the invention, the winding tool includes a wire aperture defined in the outer surface of the base structure for receiving wire guided through the base structure and guiding the wire outwardly from the base structure to form wire coils on a stator stack.
In an additional aspect of the invention, end formers are located adjacent longitudinal ends of the forming blades, and extend transversely of the forming blades and are actuated radially outwardly for engaging end turns of wire coils on the stator stacks. The outer surfaces of the end formers are contoured to be flush with the outer surface of the base structure when the end formers are in a retracted position. Further, the end formers and former blades are simultaneously actuated by the actuator structure and, in the preferred embodiment, the end formers and forming blades are each supported on a rack including a rack of gear teeth which mesh with a shaft forming a pinion gear extending through the base structure such that rotation of the shaft causes radial actuation of the end formers and forming blades.
Other aspects of the invention will be apparent from the following description, the accompanying drawings and the appended claims.